Little changes to SkAnnotation in pipe:
  - store size in the op data field rather than separately (saves 4 bytes);
  - trim out a malloc/memcpy in each of read and write;
  - remove unused enum value;
  - use the right _unpackOp function;
  - make sure we call needOpBytes().

BUG=
R=reed@google.com, scroggo@google.com

Author: mtklein@google.com

Review URL: https://codereview.chromium.org/50523004

git-svn-id: http://skia.googlecode.com/svn/trunk@12007 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pipe/SkGPipeWrite.cpp b/src/pipe/SkGPipeWrite.cpp
index 53b0ae5..50043c6 100644
--- a/src/pipe/SkGPipeWrite.cpp
+++ b/src/pipe/SkGPipeWrite.cpp
@@ -1128,18 +1128,17 @@
 
     if (base.getAnnotation() != paint.getAnnotation()) {
         if (NULL == paint.getAnnotation()) {
-            this->writeOp(kSetAnnotation_DrawOp, 0, 0);
+            if (this->needOpBytes()) {
+                this->writeOp(kSetAnnotation_DrawOp, 0, 0);
+            }
         } else {
             SkOrderedWriteBuffer buffer(1024);
             paint.getAnnotation()->writeToBuffer(buffer);
-            size = buffer.bytesWritten();
-
-            SkAutoMalloc storage(size);
-            buffer.writeToMemory(storage.get());
-
-            this->writeOp(kSetAnnotation_DrawOp, 0, 1);
-            fWriter.write32(size);
-            fWriter.write(storage.get(), size);
+            const size_t size = buffer.bytesWritten();
+            if (this->needOpBytes(size)) {
+                this->writeOp(kSetAnnotation_DrawOp, 0, size);
+                buffer.writeToMemory(fWriter.reserve(size));
+            }
         }
         base.setAnnotation(paint.getAnnotation());
     }